Disclosure relates to the field of graphical elements and is directed to a device for producing an optical effect layer (OEL). Disclosure provides an optical effect that is easy to detect as such and exhibits a viewing-angle dependent apparent motion of image features over an extended length if the viewing angle with respect to the OEL changes. OEL includes a binder material being at least partially transparent and a plurality of particles dispersed within the layer. Each particle has a non-isotropic reflectivity and may be magnetic or magnetizable. Orientation of the particles forms an orientation pattern extending over a length within an extended surface of the OEL, such that the local average of an angle between (i) a straight line along an observed longest dimension within the corresponding cross-section shape, and (ii) said first direction x varies according to a function (θ) of a position (P) along said first direction.